Different size wheels on one axle? - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Different size wheels on one axle? by Torchd on 26 Apr, 2011 00:19
• Hey guys!
  
  I have a mkIII AAZ and  I wanted to ask if I can run two different sized wheels on the front axle?
  
  Is it safe to run it or will I be causing damage to the diff?
  
  My spare is a space saver design so everytime I use it I *** my pants!
  
  Please help.
• #1 by maxfax on 26 Apr, 2011 02:57
• It's not good for the diff at all..   Very short distances at low speeds is all that "donut" spare is really intended for..  IF you don;t mind giving up a bit of trunk space, a full sized spare is darned nice..  If you have to travel any distance on your current spare, and it's at all possible, put the spare on the rear, and move one of the rear tires up front.. 
• #2 by R.O.R-2.0 on 26 Apr, 2011 09:18
• Quote from: maxfax on 26 Apr, 2011 02:57

  It's not good for the diff at all..   Very short distances at low speeds is all that "donut" spare is really intended for..  IF you don;t mind giving up a bit of trunk space, a full sized spare is darned nice..  If you have to travel any distance on your current spare, and it's at all possible, put the spare on the rear, and move one of the rear tires up front.. 
  

  
  x2, if you gotta drive more than like 10 miles, or over 40 mph, put the donut on the back and run a rear tire on the front end, then the spiders wont be constantly turning in the 3rd member..
• #3 by Torchd on 26 Apr, 2011 10:23
• Right..
  
  So the front tires have to have the exact same circumference or can it be a little different?
• #4 by R.O.R-2.0 on 26 Apr, 2011 10:26
• Quote from: Torchd on 26 Apr, 2011 10:23

  Right..
  
  So the front tires have to have the exact same circumference or can it be a little different?
  

  
  if the front tires are different sized (1/2" or so probably wont even matter) then the spiders in the 3rd member will always be turning, and will wear them, and the conical washers..
  
  think of it this way.. if you have differently sized tires on the front of your car, it will think you are constantly driving in circles. the differential doesnt know any better..
• #5 by vanagonturbo on 26 Apr, 2011 21:33
• I think overall diameter might be prudent to mention here. If both tires have the same rolling radius, it should not affect the drive-train at all. Granted, a death donut is not for autocrossing, but it shouldnt have an adverse effect on the differential if it has the same overall diameter.
  
  Perhaps the term 'tire size' should be clarified...
• #6 by R.O.R-2.0 on 27 Apr, 2011 09:14
• Quote from: vanagonturbo on 26 Apr, 2011 21:33

  I think overall diameter might be prudent to mention here. If both tires have the same rolling radius, it should not affect the drive-train at all. Granted, a death donut is not for autocrossing, but it shouldnt have an adverse effect on the differential if it has the same overall diameter.
  
  Perhaps the term 'tire size' should be clarified...
  

  
  correct, if you have 2 tires that are ~ the same diameter.. it will work. we were running a 185/70/14 on my buddies Audi 90Q, and the other 3 tires were 205/40/17s... there wasnt enough diameter difference for the car to care..
• #7 by Torchd on 28 Apr, 2011 06:09
• Okay!!
  
  
  I had to run 205/60/14 on one side and 185/70/13 on the other on front axle for about 8 kms. Did I damage my diff or am I alright?
• #8 by theman53 on 28 Apr, 2011 06:32
• nope, they are about the same rolling wise and that isn't that far. You would need a bunch of offset and much more distance to hurt it